Trapezoidal Rule

[stfnhill]

I was wondering how to use the Trapezoidal Rule in C++. My homework states this:
Integration.
Write a program to integrate an arbitrary time-­‐domain signal, with a variable sample interval and variable limits of integration. Test your program on a simulated time-­‐domain signal.

So far, I have this for my code:

#include <stdio.h>
#include <math.h>

float integrate(float,float);

int main(void)
{

int i;
int imax=100;
float result, x,y[imax];
float xscale=2;




for(i=0;i<imax; i++)


{

x=xscale*i;

y[i]=sin(x);

result= integrate(x,y[i]);


printf("%f\n",y[i]);


}





return 0;


I'm just a beginner, so any ideas at all would be greatly appreciated.

[Moschops]

What are you using to code? This hasn't been C++ since 1998.

http://rosettacode.org/wiki/Numerical_integration

[jquant]

Remember the trapezoid rule is written as follows

"((Left(n)+right(n))/2)" Where the left and right are both upper and lower estimates of the area under a curve via riemann sums.

You must incorporate the information points including a data value "x,y" and need to have a set table of values for x,y. After that you can plug it in then work it through c++. Try to take what I just wrote and do it out regularly, then try to figure it's code. Hopefully this helps.